Metformin is a generic prescription medication used to help manage blood sugar levels in adults and some children with type 2 diabetes. It works by decreasing sugar production in the liver. Learn about the side effects of metformin, from common to rare, for consumers and healthcare professionals. Overview: Metformin is medicine you take to help keep your blood sugar from getting too high. Common side effects may include stomach problems, such as diarrhea, nausea, vomiting, stomach pain. Metformin is a first-line treatment used for type 2 diabetes in adults and children 10 years and older to help improve blood sugar levels. It is also used off-label to improve symptoms of polycystic ovarian syndrome (PCOS) and other conditions. Metformin is used together with proper diet and exercise to treat high blood sugar levels caused by type 2 diabetes. This medicine reduces the absorption of sugar from the intestines, reduces the release of stored sugar from the liver, and helps your body use sugar better. Medical uses Metformin is used to lower blood glucose in those with type 2 diabetes. [15] It has also been used to help with metabolic abnormalities in polyendocrine metabolic ovarian syndrome (PMOS), and as a second-line agent for infertility in those with PMOS. [15][34] Learn more about how metformin works, its side effects, and what to expect when taking this medication. Metformin is a common treatment for diabetes. But it can cause digestive problems and other side effects. Learn more about the uses and side effects here. Metformin is a medicine that can be used to treat type 2 diabetes, gestational diabetes and the hormone condition polyendocrine metabolic ovarian syndrome (PMOS). Metformin is used alone or with other medications, including insulin, to treat type 2 diabetes (condition in which the body does not use insulin normally and, therefore, cannot control the amount of sugar in the blood).